The King pointedly avoided any suggestion of a British apology over slavery in his keynote Commonwealth speech today and insisted 'we cannot change the past'.

Charles did however acknowledge that the transatlantic slave trade 'still casts a shadow' and that 'shameful chapter of history is one that fills my heart with horror and my soul with the most profound personal sorrow'.

The 77-year-old monarch, who sounded slightly tired after a gruelling week-long Caribbean tour, has been caught in the crossfire as head of the Commonwealth between British Prime Minister Andy Burnham and Caribbean campaigners.

Mr Burnham caused a storm after saying he is open to discussions over an apology but not reparations, while protesters say the time has come for the UK to pay up. 

Addressing the issue, the King said in Antigua and Barbuda today: 'None of us, of course, would be here today were it not for our history, which has shaped us in myriad ways. History is not ours to choose or to change. 

'It is bequeathed to us in complex synthesis by forebears we can never know. Our inheritance includes both their achievements and their failures – the good they did as well as the wrongs.

'History can be hard to compass, viewed as it is through the prism of time, which can be both clarifying and distorting, and yet its consequences resonate with contemporary force.

'Our history inspires us, can appal us, yet it can always teach us. We cannot change the actions of those who came before us. We can, however, learn from the past.

'The transatlantic trade in enslaved persons still casts a shadow over these islands and other Members of our Commonwealth. As I have said before, that shameful chapter of history is one that fills my heart with horror and my soul with the most profound personal sorrow.'

The King continued in a punchy reference to Britain's leading role in also ending the global slave trade: 'And yet history also teaches us that evil need not have the last word; that character and courage can combine to overcome the most monstrous injustice, as they did with the determination to end international trade in enslaved people, in which the Royal Navy played such a leading role.

'The more I have furthered my own understanding of the issues, through listening, learning and looking, the more committed I have become to finding ways for us to work in modern partnership to address the wrongs of the past with action for the future. 

'Through improving access to education, investing in jobs and opportunities, encouraging intra-Commonwealth trade, and inspiring vital climate resilience measures across the world, I have always felt that there is so much that can be done to help lift up those who struggle against hardship and disadvantage.

'I have always tried to play my part in doing just that. For, as any sailor navigating the seas knows, we cannot command the winds, least of all where the winds of yesterday have delivered us – but we can choose how we set our sails.

'The Commonwealth of today is not merely a product of the past – it is a response to the world of today. Its vocation is more compelling than ever. 

'In fact, in a desperately troubled world, the Commonwealth has welcomed new members who see the unique value of this organisation and have chosen to be part of its future.'

Speaking to a packed audience of around 1,200 delegates, the King – wearing a grey suit and lilac tie - marked the official opening of the leaders' segment of the Commonwealth Heads of Government Meeting (CHOGM) summit.

The 15-minute speech also focused on climate change, international trade and youth opportunity.

Charles ended it by saying: 'Above all, Ladies and Gentlemen, I trust that each of you will recommit yourselves to a Commonwealth in which our young people can look to the future with greater confidence and purpose.

'So that from this remarkable family of nations, our people can draw inspiration and hope – just as I, myself, have always done.'

There was a short round of applause after his speech. The only reaction was some laughter from the room when Charles described Antigua as 'small island, big vibes'.

Mr Burnham told the King his CHOGM speech was 'perfect' afterwards.

The King hosted the prime minister at a reception for new Commonwealth Heads of Government at Weatherills Hotel in Antigua and Barbuda.

Burnham chatted with Tonga's PM Lord Fakafanua Tonga's about the Rugby League World Cup, while waiting for Charles.

The King arrived and first shook hands with Canadian PM Mark Carney.

Lord Fakafanua warmly shook the King's hand and said he 'took notes' during his CHOGM speech.

Mark Carney said it was 'very good'. Burnham then said: 'Perfect, well done.'

John Mahama, President of Ghana, and Godwin Friday Prime Minister of Saint Vincent and the Grenadines, joined the chat.

Navinchandra Ramgoolam Prime Minister of Mauritius, arrived later.

Following the speech, a choir and various performances in costume took to the stage to dance and sing a sequence of scenes for around half an hour.

They told the history of Antigua and Barbuda, with references to slavery in the performances and images in a video played out on a screen behind Charles, seeming to depict slaves working the land.

'What happened in the darkness must come to the light,' shouted one of the singing dancers, during the performance, as Charles watched from his seat.

The performances and videos also referenced climate and environmental issues. At times, Charles tapped his feet and clapped his fingers in time to the music.

After the performances, the 'family photo' was taken of all Commonwealth member states on stage.

Security around the conference centre was tight but some protestors had gathered along the roads surrounding the site ahead of the King's arrival, holding placards and wearing T-shirts which read: 'Crimes against humanity could never be legal. Apologise now'; 'You say you regret so apologise. Reparatory justice now'; and 'Apologise for the greatest crime against humanity and let's have reparatory justice.'

Accompanied by Queen Camilla, wearing a sapphire blue embroidered tunic top and palazzo trousers by Anna Valentine, His Majesty was greeted at the National Performing Arts Centre of Antigua and Barbuda, marking the start of the leaders' segment of the summit.

They were welcomed by Governor-General Sir Rodney Williams, his wife Lady Williams and Commonwealth Secretary-General Shirley Botchwey.

Inside the auditorium, the opening ceremony commenced with a fanfare followed by the National Anthem of Antigua and Barbuda played on steel drums and a short prayer. 

Later, Queen Camilla kicked off her shoes on the picturesque Fort James beach as she and the King learnt more about Antigua's environmental projects.

The King was 'shocked' to hear that 71 bags of rubbish were collected from the beach in just a two hour window this morning, while the Queen told those involved with projects focused on marine protection: 'Thank goodness for all of you.'

Chantal Miller, Founder of Island Girls Rock who have collaborated with Adopt a Coastline said of their conversation: 'He was shocked that we picked up so much in that short a time.'

The King was then surprised to learn that she is best friends with his goddaughter, Fiona Compton, and told her: 'Small world.'

The artist is the founder of Know Your Caribbean, which works to address Afro-Caribbean representation disparities in global art and media, and her father, the late Saint Lucia Prime Minister Sir John Compton, formed a close friendship the King.

Greeted by a lively band on their arrival the couple walked along the beach to meet Founder and CEO of Adopt a Coastline, Jennifer Meranto, and two Adopt a Coastline Youth Ambassador.

The couple heard how the Antiguan grassroots movement promotes long-term care for the coast environment through beach clean-ups, indigenous tree planting and community education.

The Queen was gifted a bright blue bracelet made from discarded kite surf materials which matched her sapphire blue embroidered tunic top by Anna Valentine, which she wore with white palazzo trousers and said: 'Thank you, it matches my dress!'

Their Majesties were also each handed a litter picker and both raised them up like swords, laughing.

As they took it in turns picking litter up and putting them in a black sack, the King told volunteers: 'You've done a very good job with all those bags before we got here. Is that done everyday?'

He was told they clean this beach once a month, as well as at Nevis at the other side of the island, and said: 'And you've got lots of willing volunteers?'

The King also asked if they get sargassum seaweed, which causes environmental, health and economic problems for the islands, having learnt about solutions to the issue yesterday.

Camilla was then interested to hear about Team Antigua Island Girls, who spoke about their journey to become the first all-black, all-female team to row across the Atlantic and are raising money for domestic and gender-based violence.

The Queen told one of the women: 'I raise awareness for domestic violence.'

Before leaving, Camilla told a project tasked with marine protection: 'Thank goodness for all of you.'